Aluminum-Zinc Stress Corrosion Cracking Susceptibility
Aluminum-zinc alloys with high magnesium and copper content are sensitive to cracking under tensile stress in corrosive environments. Grain boundary precipitates promote this stress corrosion cracking.
Physicochemical Mechanism of Action
Aluminum-zinc alloys with high magnesium and copper content contain grain boundary precipitates that promote stress corrosion cracking under tensile stress in corrosive environments. These precipitates can act as an electrolyte and create electrical circuits between alloy parts, leading to corrosion reactions.
Metallurgical Relevance & Welding Risks
This susceptibility to stress corrosion can lead to cracking in the weld and around grain boundaries. The cracks can propagate, especially when the alloy is in a corrosive environment or under mechanical load. This can cause component failure and safety issues.
Workshop Practice & Action Guidelines
To minimize the risk of stress corrosion and cracking, the following measures should be taken:
• Use proper welding technique with low stress and adequate cooling.
• Ensure the weld is clean and free from corrosion susceptibility.
• Apply a suitable corrosion protection method after welding, such as painting or galvanizing.